Centrifugal compressor

Abstract

A centrifugal compressor capable of rotating at high speed by means of an electric motor comprises two compression stages cantilevered one at each end of a shaft, an electric motor of which the rotor is carried by a central part of the shaft, magnetic bearings, and a magnetic stop. The motor, the bearings and the stop are placed in a housing placed under a partial vacuum. Two facial gaskets adjustable as a result of longitudinal displacement of a component and of the shaft seal the compressor and ensure sealing of the space within the housing.

We claim: 
     
       1. A centrifugal compressor capable of rotating at high speed, comprising (a) a single shaft carrying at least two compressor wheels cantilevered on its two ends for setting in motion fluid to be compressed;   (b) a high-speed electric motor comprising a rotor carried by said shaft and located in a central portion of said shaft;   (c) at least two magnetic bearings for supporting said shaft;   (d) a magnetic stop for adjusting the axial position of said shaft;   (e) a housing surrounding at least said electric motor, said magnetic bearings and said magnetic stop;   (f) at least one first facial sealing means located at one of said compressor wheels and adjustable as a result of axial displacement of said shaft by means of said magnetic stop;   (g) at least one second facial sealing means located at the second compressor wheel and adjustable as a result of a controlled longitudinal displacement of a supporting component; and   (h) circuit means for placing the space within said housing under a predetermined partial vacuum.   
     
     
       2. A centrifugal compressor as claimed in claim 1, wherein said circuit means comprises pipe means connecting said space within said housing to a suction pipe of said compressor. 
     
     
       3. A centrifugal compressor as claimed in claim 1, wherein said circuit means includes a device for generating a partial vacuum by means of suction. 
     
     
       4. A centrifugal compressor as claimed in claim 3, wherein said device for generating a partial vacuum by means of suction comprises at least one injector and means connecting said injector to a delivery pipe of said compressor.